1. Field
Exemplary embodiments of the present invention relate to a signal processing technique and more particularly, to a signal processing apparatus and a signal processing method.
2. Description of the Related Art
Image sensors sense lights and convert brightness of the lights to digital image data. A complementary metal oxide semiconductor image sensor (CIS) is one of the image sensors nowadays. Needs for a digital image processing apparatus using the CIS rapidly increase and thus functions of the digital image processing apparatus are being developed day by day. Despite the development, it is difficult to store an image of a subject as it is. According to a current status of technology, an image is stored through sampling of representative value of the subject. Recently, research is progressing in order to obtain image information as close as the subject possible.
When taking a picture of a subject having both of a bright region and a dark region, it is hard to obtain a fine image of the subject with an excellent view of both the bright region and the dark region in spite of optimal time of exposure and optimal adjustment of aperture. A wide dynamic range (WDR) technique is one of solutions to those concerns. The WDR technique is classified into a ‘multiple sampling method’ and a ‘well capacity adjusting method’. The multiple sampling method has an advantage of an excellent combination quality and a disadvantage of need for a frame memory or a plurality of line memories due to a combination of a plurality of images with time difference. The well capacity adjusting method has disadvantages of nonlinearity and image composition due to large distribution between unit pixels. In short, the WDR technique causes an unintended noise with an obtained image.